Billions of personal checks, business checks, tickets, pay stubs, vouchers, and other commercial documents are processed each year. The volume of documents being processed continues to increase despite the availability of paperless methods of making payments and/or transferring money.
The susceptibility of printed documents to fraudulent alteration costs the industry billions of dollars each year. Alteration takes the form of printing non-standard documents (forgery) and/or removal, addition or alteration of image elements on original documents. The industry is in need of methods to quickly and accurately assess the authenticity of a document and make document alteration more difficult.
Many schemes exist for printing secure documents. These generally fall into two categories, those that involve substrate manipulation and those that involve addition of image content. Examples of substrate manipulation include US20030211299 A1 which describes a coating for a retroreflective document which renders the surface of the document receptive to toners and inks printed thereon while not substantially interfering with the retroreflective properties of the underlying substrate. Methods for fabricating the document are also provided.
U.S. Pat. No. 5,888,622A provides a coated cellulosic web product and coating composition which provides enhanced toner adhesion for documents printed using noncontact printing devices such as ion deposition printers. The toner adhesion enhanced coating cellulosic product and composition comprises a cellulosic web having first and second major surfaces with at least one of the major surfaces having coated thereon a layer of a polymeric toner receptor.
U.S. Pat. No. 6,086,708A details a method of making a document, such as a check or stock certificate, having enhanced security against counterfeiting. The document includes a strip of foil having a three dimensional light diffracting image thereon affixed to the document. The strip of foil may be affixed to the document before or after the background printing or face printing of the document is completed. In this manner, the light diffracting strip may be printing on by the background and face printing of the document as desired.
Examples of methods that involve manipulation of image content or imaging materials include US20050282077A1 which describes a toner for printing documents that are difficult to chemically or physically forge and that are readily easy to visually verify and methods of using and forming the toner are disclosed. The toner includes a colorant for printing an image on a surface of a document and a dye for forming a latent version of the image underneath a surface of a substrate. An image formed using the toner of the invention is readily verified by comparing the colorant-formed image and the dye-formed image. In addition, if a solvent is used in an attempt to alter the printed image on the substrate, the dye migrates or diffuses to indicate tampering with the document.
US20050142468A1 describes a method of printing documents, for example bank checks, with a pantograph. Documents printed as described may include a digitally variable pantograph and other enhancements. The invention is particularly useful for enhanced security documents and the production thereof. US20050142469A1 describes a printing system, process and product with microprinting. Documents printed as described may include digitally variable microprint and other enhancements. The invention is particularly useful for enhanced security documents and the production thereof.
Despite these methods of security enhancement, document forgery and manipulation is still a problem.